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The Air-to-Air Missile (AAM) is a potent guided missile that changed the shape of aerial combat forever. Capable of destroying fast and maneuverable jet fighters at ranges sometimes exceeding 100 kilometers, these high-tech weapons dominate the skies. The probability of Aerial dogfights are becoming less in modern times, as US pilots have used AIM-120 missiles only dozens of times, in contrast, the US Air Force used more than 3,500 weapons against ground targets in Afghanistan during the opening nine months of 2011 alone. However the threat of it has not entirely disappeared, therefore the air-to-air missiles (AAMs) remain an essential combat element for fifth-generation jet fighters.
Since their first deployment in the late 1950s, air to air missile technologies have advanced considerably allowing them to reach targets at longer ranges, with heavier payloads and with greater precision. The speed of air to air missiles has also increased considerably, meaning that while combat jets such as the MiG-25 and SR-71 were all but immune from most air attacks during the Cold War due to their ability to exceed speeds of Mach 3, faster missiles have since been developed which are capable of downing such aircraft with relative ease. While speeds of Mach 4 have today become the norm for high end long range air to air munitions, including the Russian R-77, American AIM-120, Chinese PL-12 and European Meteor, munitions exceeding such speeds are a rarity – much less those capable of attaining hypersonic speeds over Mach 5.
Air-to-air missiles are divided into three categories: short-, medium-, and long-range. Short-range AAMs have extreme maneuverability (60 G turns) and high speed (around Mach 3 or 3 703 km/h). They can be fired at both fairly distant targets and those within dogfighting range. Medium-range AAMs are similar to their short-range cousins, but tend to have larger warheads, and have a range of around 50 km or more. This means that they can be fired at targets beyond visual range.
Long-range AAMs are, by necessity, the most advanced in the whole class of air-to-air missiles. With astonishing speed, massive warheads, and tremendous range, they can blow large aircraft out of the sky from over 100 kilometers away. They also use different guidance systems—instead of instantly homing in on targets with infrared, they generally go without guidance to a certain pre-determined point, after which they activate radar homing and chase the target. However, these missiles are difficult to develop and very few have entered operational service.
The first generation of missiles (including the first versions of the venerable Sidewinder) had seekers with a poor field of view, making them hard to fire and easy to avoid. The subsequent generation featured improved but still limited seekers. These were followed by the “third generation”, which could be fired even at targets next to the launch platform (as opposed to in front of the launch platform).
Air-to-Air Missiles with up to 30 km range, are often called ‘Dog-fight’ or close-combat missiles (CCM), or also ‘Within Visual Range’ (WVR) missiles. WVR are mostly heat-seeking, while BVR are mostly radar controlled. Some long-range missiles also use inertial guidance. The shorter range ones are typically armed with rocket motors having mostly solid fuel, but sometimes liquid fuel too. Ramjet engines, as used on the Meteor missile are emerging as propulsion that will enable future medium-range missiles to maintain higher average speed across their engagement envelope.
The fourth generation radically improved the AAM by introducing countermeasure-resistant seekers, massively increased seeker field of view, and much better agility, thanks to thrust vectoring. The most recent generation of missiles include infrared (also know as heat) seeking systems that can actually “see” the target, improving resistance to countermeasures, as well as better range and the ability to target the most vulnerable parts of the aircraft
Countries are now developing long range BVR or AAMs missiles today having ranges beyond 200 km. The new fifth generation AAMs are being fielded have many advancements they will significantly expand the ‘no-escape zone’ and increase the range over which air-to-air engagements in future can be fought, enabling pilots to exploit the capabilities of their new aircraft to the full. (The conditions under which a missile cannot be evaded through any combination of maneuvers or acceleration is termed a missile’s no escape zone.) They have higher Kill Probability against wide-bodied aircraft like AWACS, Flight Refuelling Aircraft (FRA) and Maritime Patrol Aircraft (MPA) which have low maneuverability, than against fighter aircrafts.
Air-to-air missiles are typically long, thin cylinders in order to reduce their cross section and thus minimize drag at the high speeds at which they travel. Missiles are divided into five primary systems (moving forward to aft): seeker, guidance, warhead, rocket motor, and control actuation. At the front is the seeker, either a radar system, radar homer, or infra-red detector. Behind that lies the avionics which control the missile. Typically after that, in the centre of the missile, is the warhead, usually several kilograms of high explosive surrounded by metal that fragments on detonation (or in some cases, pre-fragmented metal).
The rear part of the missile contains the propulsion system, usually a rocket of some type and the control actuation system or CAS. AAMs are typically powered by one or more rocket motors, usually solid fueled but sometimes liquid fueled. Dual-thrust solid-fuel rockets are common, but some longer-range missiles use liquid-fuel motors that can “throttle” to extend their range and preserve fuel for energy-intensive final maneuvering. Some solid-fuelled missiles mimic this technique with a second rocket motor which burns during the terminal homing phase.
Modern missiles use “low-smoke” motors – early missiles produced thick smoke trails, which were easily seen by the crew of the target aircraft alerting them to the attack and helping them determine how to evade it. The CAS is typically an electro-mechanical, servo control actuation system, which takes input from the guidance system and manipulates the airfoils or fins at the rear of the missile that guide or steers the weapon to target.
There are missiles in development, such as the MBDA Meteor, that “breathe” air (using a ramjet, similar to a jet engine) in order to extend their range. Ramjet engines, as used on the Meteor (missile) are emerging as propulsion that will enable future medium-range missiles to maintain higher average speed across their engagement envelope. The Long range AAM missiles needs to carry a large amount of fuel/propellant to travel it at high speed making them bulky and imposes structural limitations on their manoeuvrability.
Israeli Rafael Advanced Defense Systems’ Python-5 is an electro-optical missile which does not require a heat source and so is more effective against low heat source aircraft like propeller driven UAVs among others. Some missiles use thrust-vectoring, which allow the missile to start turning “off the rail”, before its motor has accelerated it up to high enough speeds for its small aerodynamic surfaces to be useful.
Latest AAMs are difficult to shake off once they’re locked on. Countermeasures include destroying the parent aircraft before the missile is launched, outrunning the missile (this can only be done if the target has enough of a lead), deploying chaff and other distractions, and hacking the seeking system with electronic countermeasures.
In parallel, there have many improvements in seeker technology, like active electronically scanned (AESA) radar, high resolution electro-optical imaging technologies with advanced digital processing that allows enhanced ability to distinguish friends from foe, distinguish countermeasures like flares from targets and choose specific vulnerable points to target. Their data links also allow them to be integrated into highly integrated combat networks for network centric warfare.
Improvements in air-to-air missiles included the combined use of several methods of guidance for greater flexibility and lethality. Active radar or infrared terminal homing, for example, were often used with semiactive radar guidance in midcourse. Also, passive radar homing, which became an important means of air-to-air guidance, was backed up by inertial guidance for mid-course and by an alternate terminal homing method in case the target aircraft shut off its radar. Sophisticated optical and laser proximity fuzes became common; these were used with directional warheads that focused their blast effects toward the target.
Saab to supply fuse subsystems for Meteor BVRAAM
MBDA has contracted Saab to supply radar proximity fuse subsystems (PFS) for the Meteor beyond-visual-range air-to-air missile (BVRAAM). The Skr150m ($18.42m) contract to supply missile subsystems will be delivered to MBDA between 2020 and 2021.
The PFS has the ability to detect the target and calculate the optimum time to detonate the warhead in order to achieve maximum effect. Saab Dynamics missile systems head Stefan Öberg said: “Meteor is designed to combat advanced air threats and its highly capable fusing system maximises warhead effectiveness and ensure the highest probability of success.
“Throughout, the PFS has proven its ability to meet all the demanding requirements placed on it.” The Meteor is a highly advanced, long-range and agile air-to-air missile system that is designed to counter the most sophisticated airborne threats, Saab stated.
